You need help from two separate and distinct professionals.
First, you need to find an attorney who is experienced in wills and trusts. Interview at least three, and select one who either has experience in moving the certificates that you described somewhat vaguely into the US according to US law, or works at a law firm that counsels international clients.
Second, you need an investment adviser. Again, interview several. All will be slick, warm, and personable. You want one that seems in tune with your goals. Beware one that listens only for a moment and then launches into a sales pitch selling you on financial instruments that you do not understand. Beware guaranteed results -- there is no such thing and if you have any doubts just ask the people who gave Bernard Madoff their life savings.
I hope this information helps you Find. Learn & Save.